A Method to Find out Perceptional Sound Composition of the Vowels in the Contemporary Turkey Turkish

Objective: The speech sounds are used in audiology and audio-verbal therapy. Perception of speech sounds is related with their acoustic properties and inner ear physiology. Therefore, a perceptional aspect of the acoustic content should not be overlooked. In this study, we evaluated linear and perceptional changes in the vowels' sound content at and over the comfortable hearing level according to dBA-filter. Methods: Recordings of 8 vowels (< a, e, i, i, o, o, u, u >) of the contemporary Turkey Turkish were filtered by a dBA-filter. Then linear frequency data (Hz) of both original and dBA-filtered files were analyzed for fundamental frequency (F0) and formants (f1 to f5) by Praat; subsequently, the data were transferred to the perceptional range (Critical Bark Bands, CBB). Results: Our data demonstrated that linear values of F0 and f4,5 did not reveal any relationship with vowels, while f1-3 presented phoneme-specific patterns. dBA-filtering did not affect linear data of f3,4 (< u > was the only exception) and f5. Linear f1va lues were increased by dBA-filter (particularly in < i,u,u >). f2 of < i, u > presented major deviations. Vowels' CBB-changes were evident in fl (the only exception was < e >), and it was evident in only f2 of < i, u >. Conclusion: It is apparent that speech sound content at and over the comfortable hearing level stimulates higher frequency bands than found in original voice. Only < e > presented no perceptional change while major changes were particularly seen in < i, u >. Thus, we could pronounce that perceptional aspect by dBA-filter would provide us with a new perspective for understanding the results of speech tests.